<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>示例1</title>
</head>
<body>
    <script>
        {
            var a = 1;
            let b = 2;
        }
        console.log(a);
        console.log(b);
    </script>
</body>
</html>